Lightroom corrupting Canon Raw files Redux

2 years ago, I brought back a few thousand images from Italy. Each day, I copied the Canon 7d raw images to a portable hard drive. When we got home, I copied from the CF cards to a folder on my hard drive. Then, I imported the contents of that folder using Copy into a new folder. I noticed that several of the images were corrupted (the purple lines/boxes that have been documented many times on dpreview). Once corrupted, the files could no longer be read by Canon's DPP. I could, however, open the files using DPP that were on the the CF card or the portable hard drive. At some point over the past 2 years, I have opened every one of the Italy images in LR. When I say open, I mean that LR has had to display the full image, not an embedded jpg or thumbnail. Over time, the number of files displaying the corruption has increased. Files that were perfectly fine 2 years ago are no corrupted.

I have seen this discussed here and in the Adobe forums. Lots of possible reasons are given, but I have to see a definitive answer that either indicts or exculpates LR as the source of the corruption. I've ruled out every potential reason that's been offered so far. I've gotten very careful, and have multiple backups of all my images, so I think I'm safe. I would love to know, though, it there has ever been an actual resolution of this corruption issue.